The information was disclosed in September by the International Consortium of Investigative Journalists (ICIJ) and a group of newspapers.

Soon after, Kroes sent to the commission an updated declaration of income in which she included earnings she had not declared since leaving her position at the end of 2014.

She was at the time receiving a transitional allowance, to which former commissioners are entitled for three years after they leave office or until they earn as much money as the amount of the allowance.

No financial loss

The commission has asked in October its ad hoc ethical committee to investigate on Kroes's case. The committee handed its report on 16 November and the commission says it followed the report's conclusions.

In its decision, the commission said that in the first case, Kroes breached the commissioners' code of conduct, and in the second she "did not act with the necessary diligence" and breached a regulation on commissioners' income.

After the former commissioner admitted that she had hidden income while receiving her transitional allowance, the commission "recovered immediately the money and thus prevented any financial loss for the budget of the union."

The commission said that the amount Kroes failed declared, since when she had failed to do so, and how much was recovered was confidential.

The EU executive found "no sufficient element nor legal grounds" to seize the EU Court of Justice or seek a financial sanction. It therefore decided that Kroes only "deserved a reprimand."

That means that Kroes will continue to receive the pension from the commission to which she is entitled.

'Reputational damage'

EU sources noted that this was the first time that a former commissioner was finger-pointed this way and that it was "reputational damage" for the 75-year old Dutch politician.

After leaving the commission, Kroes created controversy by joining the advisory board of the US car-sharing firm Uber, which she had defended when she was digital commissioner.

It was the second time this year that the commission's ad hoc committee was asked to investigate the conduct of a former commissioner.

In September the committee looked into the appointment of Jose Manuel Barroso, a two-term commission president - as non-executive chairman and special adviser on Brexit to the US investment bank Goldman Sachs.

The committee later ruled that Barroso had "not shown the considerate judgement" that one could expect and had associated the commission with 'the negative image of financial greed ascribed to the bank."

Juncker has written to former competition chief after revelations about her offshore firm. Kroes says she forgot to mention it. Her penalty, if any, will be symbolic, but EU reputational damage is growing.

Opinion

In Brussels, PR professionals and lobbying consultants are working for some of the world's most autocratic regimes. And we have no way of knowing for sure who they are, how much they are paid, or what they are up to.